Rock-drill



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Patented Oct 28 1890 R. D. HOBART 8a M. AHEARN. ROCK DRILL Jef- WITNESSES:

1 UNITED `STATES PATENT OFFICEr ROBERT D. l-IOBART, OF DENVER, AND MICHAEL AHEARN, OF LEADVILLE, COLORADO.

ROCK-DRI LL.

SPECIFICATION forming part of Letters Patent NO. 439,275, dated October 28, 1890.

Application filed November 12, 1888. Serial No. 290,556. (No model.)-

To all whom it may concern:

Be it known that we, ROBERT D. HOBART, of Denver, in the county ot Arapahoe, and MICHAEL AHEARN, ofLeadville, in the county of Lake, and State of Colorado, citizens of the United States, have invented certain new and useful Improvements in Rock-Drills, of which the following is a specification, refer'- ence being had therein to the accompanying drawings, enabling any one skilled in the art to which the invention pertains to practice the same.

Our invention relates to an improved construction of rock-drills of that class or type wherein the drilling is eected by the use of rotating cutting or drilling edges; and its objects are to furnish a drill having a pair of expansible cutting-jaws, so that the diameter or bore of the hole drilled or being drilled may be enlarged at any desired point to such extent as is permitted by the amount of expansibility given such jaws, and so constructed, also, that these jaws may be instantly will, such expansible and controllable jaws being combined, when desired or deemed necessary, with any of the ordinary types of nonexpansible drill heads or points, the whole being of simple yet strong construction, edicient and reliable in operation, readilyT controlled and operated, and durable inuse; to which ends the invention consists in the features, arrangements, constructions, and cornbinations more particularly hereinafter described and claimed.

In the drawings is illustrated an embodinient of our invention, wherein--4 Figure l is a front View or elevation of our improved drill detached from the supporting tube or pipe; Fig. 2, an enlarged vertical section of the drill on line a; a', Fig. l, in position at the end of such tube or pipe; Fig. 3, a top view of the spindle or shank thereof; Fig. 4, a vertical section of a part of the drill, taken in a plane at a right angle to the plane of Fig. 2; Fig. 5, a vertical section of the bottom of a well and its tubular casing.

In the figures is represented a complete drill for operating any suitable drilling or cutting ring or disk or drill-points, the reference-numeral 2 indicating a socket for the reception and retention of such ring or disk, such socket being formed with or secured to the end of a shank 3, tapered upon two opposite sides, the tapers or inclines of such opposite sides being regularly inward from the top or some other point a little distance above the socket down to the socket. Upon these inclined or tapered sides are the ribs 4t 4, extending down to or about down to the socket 2. Each is undercut as to both its side walls, as shown at 5, so that the tops of such ribs are wider than their bases, and longitudinally through the center ofthese slots and the body of the shank is formed a slot 6, for a purpose hereinafter noted.

At the top of the shank, and somewhat smaller than the bodyof the shank, is ascrew 8 or other suitable fastening device, by which the whole drillhead is aftixed to the tube 19, to extend to the exterior of the drilled hole for the'conveyance of power and water to the head.

9 9 are the expansible jaws, two being used as giving from their location opposite each other on the inclined ribs et et equal resistance in work on both sides of the shank, and hence greater steadiness thereto. Each should be curved on its exterior either as to all or part thereof, and should also incline inwardly on its exterior from its lower edge or point where its cutting devices are placed to give better clearance. Each has a longitudinal groove along its inner center or iia-t surface, such grooves being undercut, as shown, to correspond and tit upon the Aunder-cuts of the ribs 4, whence it is evident that if the jaws 9 be slid from the top upon such ribs 4 they are locked thereto in rotary motion, but that horizontal or'longitudinal movement of either the shank with its socket 2 or the expansible jaws 9 0 is permitted relatively to each other. These jaws are of such size that when lying, as theynorinally do, at the lower end of the shank and upon oras near to the socket as permitted, they will come within the area ofthe bore made by the drilling device carried by the socket and readilypass therethrough; but it is readily seen that if raised. upon the inclined ribs 4 4 they will be thrown outwardly pro- IOO g ai

portionately to the incline of such ribs in the distance they are raised and ream or drill beyond the drilling limitof the ring or disk carried by the socket 2, and means for suoli raising will now be described. Through the center of the shank 3 is a longitudinal aperture 7, forming a guide and a sea-t for a piston-rod 15, carrying at its upper end a piston 16, provided with any customary or suitable packing, and situated within the cylinder 17, secured upon a reduced portion of the screwtop 8 by a male and female thread or by any other suitable means. The cylinder 17 extends upwardly within the tube 19 and is of a length somewhat greater than the amount of movement to be given to the expanding-jaws 9 9. Near its base one or more perforations 1S are made through its wall, whereby water may pass to its interior from the tube 19.

As before stated, a longitudinal slot 6 is made. entirely through the ribs 4 4 and shank 3. In addition thereto ahole for the reception of a pin is made through the lower end or in the lower part of the piston-rod 15. In each jaw 9 a hole for the reception of a pin or screw 13 is made through its wall into its interior groove, and just above such hole a chamber or recess 12 is formed. The jaws 9 9 being placed upon the ribs 4 4 and the piston-rod 15 put in position, the parts are put in such relation that the holes for the pins or screws 13 13 and the one in the piston-rod and the slot 6 coincide or are in line, when a pin 14, of length about equal to the distance from the outer en d of one chamber 12 to the outer end of the other when the jaws 9 9 are in their normal or lower position, is passed through the holes and the slot, securing the jaws to the piston-rod. The piston-rod being then slightly raised, the pin 14 passes into the chambers 12, whereupon blind screws or pins 13 are placed in the holes therefor, extending inwardly nearly or quite to the piston-rod. The outer walls of the chambers 12 12 prevent the pin 14 from becoming detached from the jaws and pistonrod, while the blind screws or pins, as either is used, retain the pin within such chambers.

It should be noted that the parts should be adjusted so that when in normal position the piston 16 may not fall within the cylinder 17 below or even quite to the apertures 18, in order that water entering the cylinder shall always enter below the piston. The pistonrod should be so fitted to the aperture in which it works in the shank 3 that there may be an escape of water around the same, and that such escape shall be slower than the inlet through the perforations 18, that a pressure of water may be had within the cylinder 17 when necessary. To this end the contracted part of the piston-rod 15-that is, the part below the shoulder QO-eis slightly sm aller than the passage through the shank it takes in, a small passage 10 being thereby left around that part of the piston-rod. lVhen thev piston is raised to a suic'ient height within the cylinder 17 to throw the g jaws 9 well out, the larger part of the piston-rod passes out of the aperture through the shank and the water escapes below the shoulder 20 and around the smaller part of the pistonrod.

Supposing it be desired to enlarge the bore of a drill-hole at any point of its length or its depth, the drill-head attached to the tube 19 is inserted therein to the proper point. W'ater un der proper pressure is then admitted to the tube 19, and such proper pressure maybe 0btained by mere heightof column, or, where such heigth of column is not attainable or the position of the tube will not give the pressure, by forcing or pumping Water into the tube 19. Such water, with whatever pressure is given it, enters the cylinder 17 between the piston 1G and top of screw-head 8, forcing the former upwardlyin the cylinder. As it rises it carries, through the medium of the pist-onrod, the jaws 9 9 up the inclined ribs 4 4, so that their cutting devices are thrown outwardlybeyond the plane of any cutting devices carried byaring or disk in the socket 2 and operate on material beyond the drilling limit of the latter. lVhere a mere enlargement at some point is desired, a ring or disk in socket 2 need not be used; but where a well or drill-hole is to be deepened or a casing extended in a drilled well beyond a point at which the casing then extends, a drill ring, disk, or points should be used in the socket, that the bore may be kept uniform, a drill-head of size sufficient to pass through the well or its casing being used and the enlargement beyond that made by the use of the expansible jaws. So long as this requisite pressure of water is maintained the jaws will be kept in the elevated and outwardly-thrown or operative position; but so soon as such pressure is removed they will by their own gravity fall to their normal or inoperative position, so that they are readily controllable by the application ot' water-pressure to or the withdrawal thereof from the pistou within the cylinder.

It is evident that the expanding-jaws and inclined ribs, instead of being kept in sliding engagement by regular inclined under-cuts or bevels, as shown, could be kept in such engagement by a groove on one part and a rib upon the other, similar or akin to a feather and spline. N o mattei', however, what means of keeping these parts in sliding engagement are used, it is readily seen that if the cutting or drilling edges of the expansible jaws take upon a ledge or shoulder of sufficient hardness within a well or drill-hole the resistance of such shoulder and the gravity of the head will cause the jaws to be'thrown upward and expanded to enlarge the bore of the hole automatically and without the use of the piston and the water to act thereon. For instance, referring to Fig. 5, suppose 2l to be the casing of a drilled hole or well resting upon the shoulder or bottom 22 of the drill-hole. Usually a pocket 23 is'formed either by the action IOO IIO

of water or 4other causes in the matter 24; but, whether such a pocket be formed or not, suppose it be desired to deepen such well or other drill-hole and so deepen it that the casing and bore may be of uniform size. In such case the casing is lifted to a short distance-for instance, to the dotted line 25-and the drill with the expansible jaws lowered. When the drill-head reaches the point below the line 25, the expansible jaws may be thrown out automatically by contact with the shoulder 22 and take thereupon, enlarging the bore, so that when desired the casing may be forced to the bottom of the addition of the well or drill-hole, or they may be thrown out by the action of the piston operated on by water admitted to its cylinder.

Having thus described our invention, what we claim is- The combination,in a drill-head, of a shank tapered on opposite sides and having ribs upon such tapered or inclined sides, expansible jaws located and adapted to slide upon such ribs, a piston-rod moving in an aperture in the shank of the drill-head and secured to the jaws, a piston at the outer end of such rod, and a cylinder upon the end of the drill-head, Within which such piston plays, and having inlets for water between the end of the drill-head and the piston, substantially as set forth.

In testimony whereof we atlix our signatures in presence of two witnesses to each.

ROBERT D. HOBART. MICHAEL AHEARN. lVitnesses to signature of Hobart:

Z. F. WILBER, WILLIAM R. BARBOUR. lVitnesses to signature oi' Ahearn:

A. LYNCH, JOHN K. RYAN. 

